1. Field of Invention
Methods and devices consistent with the present invention relate to signal processing and voice command recognition, and more particularly, to learning voice command instructions, which have erred previously, through learning about repeated mistakes.
2. Description of the Related Art
In voice command recognition technologies, it is important to recognize input voice command instructions. Accordingly, existing voice command recognition techniques have learned voice command to adapt themselves to various input environments in order to achieve a high recognition rate even when input voice command signals are distorted.
FIG. 1 is a flow chart showing a related art voice command recognition and learning process.
Referring to FIG. 1, first, a signal processing apparatus activates a voice command recognition function (S101).
When voice command is input from a user (S102), the signal processing apparatus recognizes the input voice command (S103).
Then, the signal processing apparatus outputs the recognized voice command (S104) and performs an operation based on a result of the recognition (S105). The signal processing apparatus determines whether the user stops the operation which has been performed (S106). If the operation does not correspond to a control instruction intended by the user, the user may stop the operation being performed by the signal processing apparatus. That is, if a result of the voice command recognition is different from the one that the user has intended (or if the voice command recognition fails), the user may cancel it and input voice command again. Accordingly, if the operation is stopped by the user, the signal processing apparatus is again input with a voice command instruction from the user. On the other hand, in case where the operation is not stopped by the user, the signal processing apparatus calculates reliability of recognition result (S107).
The signal processing apparatus determines whether or not the calculated reliability exceeds a predetermined level. If it is determined that the calculated reliability exceeds a predetermined level (S108), the signal processing apparatus learns the recognized voice command (S109). However, if it is determined that the calculated reliability is below a predetermined level, the signal processing apparatus is again input with a voice command instruction from the user.
In the related art, if voice command recognition was successful and a result of the voice command recognition was determined to have a reliable level, the successful voice command was re-learned using corresponding data. For example, after temporarily storing a voice command recognition result and a feature vector calculated in the voice command recognition, if it was determined that the voice command recognition was reliable according to an aspect of apparatus operation by a user, the successful voice command was used for re-learning.
Accordingly, if voice command recognition failed or if it was determined that the voice command recognition result did not reach a reliable level since reliability of the voice command recognition was below a predetermined level although the voice command recognition had been successful, re-input voice command was not learned.